There are in-vehicle emergency report apparatuses so constructed that emergency report operation can be performed with reliability when a starting trigger for emergency report operation occurs. For this purpose, these in-vehicle emergency report apparatuses are so constructed that the following operation is performed: when the supply voltage of a vehicle battery drops, for example, on starting an engine, the operating power source is switched from the vehicle battery to an auxiliary battery.
(Refer to Patent Document 1, for example.)
                Patent Document 1: JP 2000-322677 A (corresponding to US2004/0075345 A1)        
When the operating power source is frequently switched from a vehicle battery to an auxiliary battery, the capacity of the auxiliary battery is accordingly reduced. To reduce the burden of replacing an auxiliary battery in addition to other purposes, it is desirable to minimize the frequency of operation of switching the operating power source from the vehicle battery to the auxiliary battery. The technique disclosed in Patent Document 1 is so constructed that the operating power source is switched from the vehicle battery to the auxiliary battery each time the supply voltage of the vehicle battery drops, for example, on starting the engine. This operation is performed even though it has no relationship whatsoever with emergency report operation. Therefore, the operating power source cannot be effectively switched from the vehicle battery to the auxiliary battery, and this uselessly consumes the capacity of the auxiliary battery.